The discovery of new therapeutic agents having increasingly complex molecular structure has presented new challenges related to how they can be efficiently delivered to targeted sites. For example, recent developments in recombinant DNA technology and human genome characterization have enabled identification of the moleculer origins of many genetic and acquired diseases and construction of appropriate plasmids containing desired genes. However, the efficient delivery of these large and heavily charged constructs, having molecular weights of up to tens of millions of daltons and containing several tens of thousands of negative charges into cells remains a substantial challenge. Studies evaluating the use of neutral and cationic liposome structures as vehicles for the delivery of polynucleotides to cells have met with limited success, as these encapsulated structures are rather large and unstable.
Accordingly, compounds that can be used as effective vehicles for the efficient delivery of large complex agents, such as polynucleotides, to cells would be highly desirable.